In recent years significant advances have been made in the art of data collection devices and networks containing the same.
In U.S. Pat. No. 5,900,613, a data collection device system is described having a data collection device adapted to read bar code data wherein the data collection device is in communication with a local host processor and a remote host processor. The data collection device is configured to report bar code data to a remote computer and execute reprogramming routines to receive program data from either or both of the remote host processor and the local host processor.
In U.S. Pat. No. 6,298,176, a data collection device system is described having a bar code reading device and a host computer. The bar code reading device is equipped to send bar code data and associated image data to the host. The image data may contain digital images associated with transmitted bar code data. In one example, image data sent to a host includes image data representing a handwritten signature.
In U.S. Publication No. US2002/0171745, a data collection device system is described having a bar code reading device which is in communication with a remote computer. The bar code reading device sends image data and associated bar code data to the remote computer. In one combined bar code/image data transmission scheme, an image data file in .PDF, .TIFF, or .BMP file format is created at a data collection device which includes an image representation of a decoded bar code message and an image representation of the package including the bar code encoding the decoded message.
In U.S. Publication No. US2003/0132292, a data collection device is described having a data collection terminal including a bar code reading unit, an RFID reading unit, a mag stripe data reading unit, a chip card reading unit, and a fingerprint reading unit. The terminal is part of a data collection system, which is configured to facilitate financial transactions involving data collected utilizing the various reading units.
U.S. Pat. No. 6,832,725 describes an optical reader imaging module that includes a first circuit board carrying a two dimensional image sensor; a second circuit board; a support assembly between the first and second circuit boards; an aiming system for projecting an aiming line using LEDs mounted on the first circuit board; and an illumination system for projecting an illumination pattern on a target area using illumination LEDs on the second circuit board. The aiming LEDs are selected to emit light in a different visible color relative to a visible color emitted by the illumination LEDs.
The above documents are generally directed to 2D imagers; however, the present invention is also applicable to 1D imagers. Such an imager is described, for example, in U.S. Pat. No. 6,119,939, which is directed to an optical assembly for use in a reader having an optical axis. The assembly includes a support frame having a rear housing containing a solid state imager; a single imaging lens mounted in the frame for focusing a target image upon the solid state imager along a linear optical axis; an illumination unit mounted in coplanar alignment on each side of the frame (each unit containing at least one lamp mounted behind a field stop aperture); and a cylindrical illumination lens mounted in front of each field stop aperture, for focusing a horizontal line of light upon a target in barcode space.
The disclosures of the above patents and published patent application are hereby incorporated in their entireties by reference thereto.
In current hand held data collection devices, which include corded and cordless bar code scanners, portable data terminals, transaction terminals (including price checkers), and bar code verifiers, light-emitting diodes (LEDs) can be used as indicators (for example, a “good read” indicator), and more importantly, for illumination.
Illumination can take two forms; aiming (also called targeting) illumination, and acquisition illumination. In the case of aiming illumination, an optical system projects a user-visible alignment indicator that assists in optimizing the spatial relationship between the imaging system of the data collection device and the target indicia, in order to facilitate image acquisition. For example, using one or more LEDs or a laser diode together with an appropriate optical system, the user may see cross-hairs, corner brackets, one or more dots, a line, or combinations of these, projected onto the substrate bearing the target indicia. These provide visual feedback to the user to assist in placing the imaging system of the data collection device and the target indicia into an acceptable read position relative to each other.
In the case of acquisition illumination, LED illumination is projected towards a target, such as a bar code indicia on a substrate, and the resulting scattered light from the target passes through the optics of the data collection device to impinge on the sensor array. This sensor array may be a linear (1D) array; or, a row-and-column (2D) matrix, such as a CCD or CMOS device. As used herein, the term “light” means those electromagnetic wavelengths produced by the LED, including but not limited to wavelengths in the visible spectrum. While conventional data collection devices employ visible light, and primarily white, red, blue, and/or green, for targeting and image acquisition illumination, this is not a requirement, and depending on the environment of use and overall system capabilities, other wavelengths or portions of the spectrum, both visible and invisible such as infrared and ultraviolet, may be used as well.
The amount of light, both ambient and that generated by the data collection device, is an important factor in its performance. With regard to light generated by the device, the amount of light and the amount of power required to produce it are factors in whether an image can be acquired at all (for example, under low light and/or long range conditions); in the time needed to acquire the image (for example, higher illumination can improve contrast levels, decreasing the time needed to recognize and/or acquire an image, or conversely can produce glare or specular reflection, impairing image detection and acquisition); in the quality of the image acquired; in whether it is necessary or desirable to alternate or combine the use of aiming illumination and acquisition illumination sources; and, in the case of a battery-powered device, in balancing power conservation with performance. When reading 2D symbologies the aiming illumination is usually turned off when an image is being acquired in order to ensure a constant illumination over the field of view. This may also improve power conservation. When reading 1D bar code symbols or some 2D bar codes on the other hand, conditions such as low ambient lighting, relatively large distances, and relatively poor quality of the indicia may favor leaving the aiming illumination on when the acquisition illumination is energized, effectively turning the aiming illumination into an auxiliary form of acquisition illumination in order to maximize the light reaching the target indicia.
These often conflicting needs can force a choice that sacrifices one interest for the other, and may prompt additional hardware and software expense and complexity in the design and operation of a data collection device in an attempt to balance the competing factors or provide the user with a range of options.
Accordingly, there is a need for further advances in data collection devices, specifically regarding the sources and uses of the illumination used for aiming and acquisition.